The process of converting an RC car to a Rover consists of adding an
autopilot board in between the RC receiver and the car’s motor and
steering servo. We recommend that the controller be powered by the
included Power Module.

Note

This tutorial assumes you’re using a Mode 2 radio setup. If you’re
using Mode 1, the throttle will move to the other stick

Rover is designed to use regular RC transmitters (not specialized RC car
transmitters) with both throttle and steering on the right stick in Mode
1 or left stick in Mode 2 - typically the elevator stick. This is
because RC cars can typically go both forwards and backwards and so the
throttle should be spring-loaded to return to the mid-point. If however,
you are not using a RC car motor controller (ESC) but rather a regular
aircraft motor controller (ESC), which typically does not have a reverse
function, you can put the throttle on the left stick as would normally
be the case for an aircraft.

For standard RC cars that use a servo to steer, use the Car settings.
If, however, you have a treaded tank or some other vehicle that uses
different speed motors on each side to steer, use the Skid Steer
settings.

The below shows a typical setup in a small rover, using APM2.x, 3DR
radio telemetry and both sonar and IR sensors (instructions on setting
them up are here). Note a few elements:

The RC car’s plastic body shell has been removed and a plywood sheet
cut and drilled to fit on the mounting posts.

APM2.x has been raised up on a platform made of four 30mm nylon
spacers, four 5mm nylon screws, and a Copter stack-up plate.
This is to ensure that the sensitive compass sensor on APM is as far
as possible from the magnetic noise/interference of the car’s
electric motor.

APM, the GPS, 3DR radio and RC receiver are all powered by the APM
Power Module (included with the APM set). The car’s steering servo is
powered by the car’s speed controller. This is the standard setup and
doesn’t require any special settings or configuration, but for those
wondering about power, that’s the answer. Among other advantages, the
use of the APM Power Module means that APM can do voltage and current
sensing and report battery status to the Ground Station during the
run, as well as data log it for after-run analysis.

A larger battery than the car was originally designed for is being
used (because the rover is designed to travel long distances
off-road), and it is mounted on velcro under the APM platform so it
doesn’t shift.

Depending on the car frame you’re using, you may wish to set up your
gear differently. Almost any configuration can work, but just remember
to keep APM’s far from sources of magnetic interference as possible! The
image below shows a top view of Tom Coyle’s Slash Rover (winner of the
Peloton Class at AVC 2013) with a Spektrum receiver, GPS, and external
compass.

3DR GPS uBlox with Onboard Compass is intended for use with APM2.x (for
external compass). It provides enhanced compass performance because of
the freedom to situate the GPS unit in an optimal position independent
of the location of the APM.

Place your GPS in an elevated position on your rover with the arrow
facing forward (toward the front facing direction of your rover).
Connect the GPS module to the APM using the two cables included with the
GPS as shown below.

3DR GPS uBlox with Onboard Compass includes two connector cables: one
4-position cable and one 5-position-to-6-position cable. To connect the
GPS module to APM, connect the GPS to the APM GPS port using the
5-position-to-6-position cable; connect the GPS to the APM I2C port
using the 4-position cable.

3DR GPS uBlox without Onboard Compass is intended for use with APM2.x.
To install your GPS module without compass, mount to the top of your
rover and connect to the APM GPS port using the 5-position-to-6-position
connector cable.